Sealing a carbon ribbon to a core



Ja n.2,1968 J. MRI-1M ETAL 3,361,244 SEALIN" YRBON R Filed April 29, 1966 2 Sheets-Sheet 1 FIG. 2

I INVENTORS.

JOHN P ARENA -y ALWYN B. PERRY AGENIT. v

Jan. 2, 1968 ARENA ET AL, 3,361,244

SEALING A CARBON RIBBON TO A CORE Filed April 29, 1966 2 Sheets-Sheet 2 FIG. 5 I, we?

IN VEN TORS.

JOHN P ARENA y ALWIN B. PERRY AGENT.

United States Patent 3,361,244 SEALiNG A CARBON RIBBON TO A CORE John P. Arena and Alwyn B. Perry, Lexington, Ky., assignors to International Business Machines Corporation, Arrnonk, N.Y., a corporation of New York Filed Apr. 29, 1966, Ser. No. 546,357 8 Claims. (Cl. 197151) This invention relates to typewriter ribbons, and more particularly to a method of sealing one end of a carbon typewriter ribbon to a core, and to the product produced by the method.

In typewriters, in order to produce a particularly high quality of type impressions, carbon ribbons are often used. There ribbons are progressively unwound from a wound supply and then rewound after passing the printing station, the rewound ribbon being generally discarded when the wound supply is exhausted. The ribbons are formed of a thin substrate, usually paper or plastic, coated on one side only with a carbon ink having a wax base. In the overall process of manufacturing a carbon ribbon for use in typewriters, the final manufacturing phase comprises the process of winding the ribbon about a core to produce the wound ribbon supply. In this phase of the manufacturing process, one end of the ribbon is first attached to the core to facilitate winding the ribbon about the core.

One prior art method of attaching the end of the ribbon to the core involves the use of an adhesive substance, originally placed either on the core or on the end of the ribbon, to secure adhesion between the ribbon and the core. Another known method for attaching the ribbon to the core involves the use ofa short piece of tape, coated on one face only with an adhesive substance, to attach the ribbon to the core.

Still another known method for attaching the ribbon to the core involves the use of a tape coated on both faces with an adhesive substance. This tape is wound about a portion of the core, to which it adheres, and the ribbon is then caused to adhere to the other adhesive side of the tape which faces outward from the core.

Since the carbon ribbon is fed only once through the typewriter, and then discarded, it is desirable that the end of the ribbon which has been attached to the core should peel from the core with little or no resistance. Thus, when the wound supply of ribbon is exhausted, the used ribbon can be easily wound upon the take-up reel and be conveniently discarded. It is because of the desirability of this feature that the above methods for fastening the ribbon to the core have proved to be unsatisfactory. Often, when any of the above methods are used to fasten the ribbon to the core, the bond between the core and the ribbon is strong enough to cause the ribbon to be torn or stretched in the typewriter when the ribbon is nearly exhausted. Stretching of the ribbon can cause the carbon ink to flake off of the ribbon at various points. Also, as the ribbon stretches, it will not properly pass the printing station. The keys of the typewriter may then strike the same area of the ribbon several times in succession resulting in a loss in quality of type impression.

Another previously proposed solution to this problem involves the use of so-called low tack adhesives which 3,361,244 Patented Jan. 2, 1968 would permit the end of the ribbon to peel from the core with little resistance. However, this also has proven to be unsatisfactory because some of the adhesive adheres to the ribbon as it is peeled from the core and is then deposited in varying amounts upon parts of the typewriter as the ribbon goes through them. This necessitates relatively frequent cleaning of the ribbon path in order to remove accumulations of the adhesive substance and other foreign matter which adheres to it.

A further disadvantage of using adhesives is that they impart to the ribbon a tendency to curl. Because of the tendency to curl and because even low tack adhesives will stick with some degree of strength, ribbons with adhesive on them have been found to hang up or get caught in the narrow guides which support the ribbon.

It is therefore an object of this invention to provide a carbon typewriter ribbon in which the ribbon is fastened to the core in an improved manner.

It is a more particular object of this invention to provide a typewriter ribbon of the type described wherein adherence of the ribbon to the core is suflicient for the manufactur-ing process and wherein the ends of the ribbon can be peeled from the core with very little resistance after the ribbon has been used.

Another object of this invention is to provide a typewriter ribbon which accomplishes the above and which passes cleanly through the typewriter without depositing foreign matter in its path and without sticking to the guides in the typewriter.

It is a further object of this invention to accomplish the above through the use of an improved process for attaching the ribbon to the core.

In accordance with one aspect of the invention, there is provided a carbon typewriter ribbon. and method of making the same, wherein the wax base of the carbon ink itself is used to attach one end of the ribbon to thecore. The ribbon is attached tothe core through the use of a heated sealing bar which softens the wax base of the carbon ink which then, after cooling, adheres to the core of the typewriter ribbon.

One advantage of this typewriter ribbon over those previously used is that, when the end of the ribbon is reached, it is peeled from the core with practically no resistance or stretch whatsoever. There will therefore be no tearing of the end of the ribbon or flaking of ink into the typewriter from the ribbon.

A further advantage of this invention is that no adhesive substance or other foreign matter is introduced onto the ribbon. The end of the ribbon will therefore pass cleanly through the typewriter without leaving objectionable foreign deposits in its path or getting caught in the narrow guides supporting the ribbon.

Still another advantage of this invention resides in its ease of implementation. The steps of the novel process for attaching the end of the ribbon to the core can easily be incorporated into any one of a number of existing processes for the production of carbon typewriter ribbons.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 shows a carbon ribbon assembly.

FIG. 2 shows a cross-section of a carbon ribbon.

FIG. 3 shows some of the details of a slitting and winding machine that may be used for typewriter ribbons.

FIG. 4 shows the slitting and winding machine at another stage in its operation.

FIG. 5 shows an empty core just prior to sealing a ribbon to it.

FIG. 6 shows apparatus that may be used for the sealing process.

FIG. 7 is a cross-sectional view on the line 77 of the apparatus shown in FIG. 6.

FIG. 8 shows the use of the heat sealing apparatus with the slitting and winding machine.

FIG. 9 shows details of the sealing operation of FIG. 8 where the ribbon passes against the core.

In order to avoid confusion, the terms ribbon and typewriter ribbon will be used in this specification to refer to the inked strip which passes through the typewriter and is used in the process of producing printed indicia on paper. The term ribbon assembly will be used when referring the combination of a ribbon wound around a core.

Referring to FIG. 1, there is shown a typical carbon ribbon assembly. The ribbon assembly comprises a carbon ribbon 1 wound about a cylindrical core or carrier 2. In the center of the core, there is provided a hole 3 so that the ribbon assembly may be mounted on an appropriate receiving device of a typewriter (not shown). The outer end of the ribbon 1 may be held in place by a strip of tape 4 in order to prevent the ribbon from unraveling during shipment and handling. Also, the outer end of the ribbon may have attached to it an uninked leader 5 made of thin poly-vinyl chloride or other suitable material so that a typist may thread the leading end of the ribbon through the type-writer and to a take-up spool without soiling her hands.

Referring to FIG. 2, there is shown a cross-sectional view of the carbon ribbon 1. The ribbon comprises a substrate 8 coated on one side with a wax based carbon type ink 9. The substrate 8 may be made of paper, plastic, or other suitable thin, flexible material. Inks generally used in these ribbons contain coloring materials suspended in a wax base. The ribbon is generally wound around the core in such manner that its inked surface 9 becomes the inner surface (i.e., the surface facing the core).

Although the ribbon used in a typewriter is on the order of inch in width, the ribbon material is manufactured in much wider widths. Thus, before being wound upon a core, the ribbon material must be slit into appropriate widths.

Referring to FIG. 3, there are shown certain details of a slitting and winding machine that may be used for slitting the ribbon material and winding it about a core. As the wide inked ribbon material is unwound from a feed roll (not shown), it may be slit by knives (not shown) into appropriate widths. The ribbons 1, now slit to their proper widths, are then fed under a tension roller 11 to cores 2 mounted upon a rotatable member 12. As shown in FIG. 3, the uninked surface of the ribbon 1 contacts the tension roller 11, and the ribbons are wound upon the cores 2 in such manner that the inked surface of the ribbon faces inward toward the center of the core 2. The rotatable member 12 is caused to rotate in the direction shown by the arrow until the proper amount of ribbon has been wound around each core. During the winding operation, more empty cores 2 may be placed upon a second rotatable member 13. After the proper amount of ribbon 1 has been wound about the cores 2 on rotatable member 12, the entire assembly may be rotated in the direction of the arrow to bring it into the position shown in FIG. 4.

Referring to FIG. 4, essentially complete ribbon assemblies 15 are on rotatable member 12 and a number of new cores 2 are on rotatable member 13 ready to receive ribbon. The portions of the slit ribbons 1 that pass over the new cores 2 as they come from the feed roll will now be attached to the new cores 2 and the portion of ribbon extending between the new cores 2 and the completed ribbon assemblies 15 will be severed to permit removal of the completed ribbon assemblies. Then, while ribbons are being wound about the cores 2 on rotatable member 13, the completed ribbon assemblies 15 will be removed from rotatable member 12 and new cores will be placed on it.

Referring to FIG. 5, there is shown a new core 2 with a ribbon 1 passing over it. The ribbon contacts the core along the area 17 and, in accordance with one aspect of the invention, will be attached to the core by the application of heat and pressure over the area 17. The heat applied must be sufiicient to soften the wax base of the carbon ink which coats the surface of the ribbon 1 facing the core 2, but the amount of heat applied should be below that which would cause liquefaction of the wax base. The pressure required is very small and need be only sufficient to maintain contact between the ribbon and the core.

Inks generally used for these typewriter ribbons are of the so-called hot melt type and commonly contain approximately 45-50% wax, but it is recognized that the amount of wax used in commercially available inks can vary over a still broader range. For a hot melt carbon ink, approximately 4550% of which is a mixture of Montan, paraffin and carnauba, a temperature of approximately F. applied for about 2 seconds is sufficient for the sealing operation. The temperature of 170 F. is approximately equal to the liquefaction temperature of the wax-based ink.

Although many different kinds of waxes may be used in hot melt carbon inks, the characteristics of these waxes are well known and it is unnecessary to discuss them here. The temperature used must be at least sufficient to reduce the wax to a plastic state, and optimum results are obtained when the temperature is either above the melting point of the wax-based ink or within 5 F. thereof. For example, if the wax-based ink melts at 170- F., then the temperature used in this process is preferably at least 165-1 75 F.

It is, of course, recognized that there are many ways to bring the wax-based ink to the required minimum temperature. Instead of using a sealing bar heated to the minimum temperature and holding the bar against the ribbon for a few seconds, one could use a much hotter bar and touch it to the ribbon for a very short time. The primary factors imposing an upper limit on the temperature used are such things as safety of employees, prevention of heat damage to the equipment, and prevention of heat damage to the core or the typewriter ribbon substrate. It would also of course be undesirable to vaporize the wax-based ink.

Referring to FIG. 6, there is shown apparatus which may be used to seal the ribbons to the cores. The apparatus comprises a hollow handle 20 connected by spacers 21 to a sealing bar 22. The sealing bar 22 is supplied with electric current through wires 23 and 24, wire 24 passing through the hollow handle 20 attached to the bar.

Referring to FIG. 7, more details of the apparatus may be seen. One surface 25 of the sealing bar is curved to conform to the surface of the cores. Attached to the surface 25 and conforming to its curved shape is a strip of Nichrome or other suitable material 26 which will be heated to the proper sealing temperature by an electric current passing through it. The wires 23 and 24 (shown in FIG. 6) are attached to the ends of the strip 26 to supply electric current to it. To facilitate severing the ribbon in order to allow removal of completed ribbon assemblies, there may also be provided a knife edge 27 adjacent to the heated element 26. To assist in severing the ribbon, the knife edge 27 may also be heated in the same manner as is the element 26.

Referring to FIG. 8, the use of the above-described sealing apparatus will be described. Completely wound ribbon assemblies appear on the member 12. Empty cores 2, ready to receive ribbon, are on the member 13. Ribbons 1 pass from a feed roll (not shown) over the empty cores 2 to the wound ribbon assemblies 15. The sealing bar is held against the ribbon 1 passing over the cores 2 as shown in FIG. 8.

Referring to FIG. 9, more details of the sealing oper ation may be seen. As the ribbon 1 passes over the empty core 2, the heated element 26 of the sealing bar 22 presses the ribbon 1 against the core 2. When the heating element 26 is brought to the proper temperature as described above, the wax base of the ink which coats the surface of the ribbon 1 that contacts the core 2 will soften. Upon removal of the heating bar 22, the wax will cool and bond the ribbon 1 to the core 2.

In order to minimize the possibility of damage to the core or to the ribbon, it is preferred that the heating bar be applied for a short time. Generally, two to four seconds will be sufficient if the heating bar is heated to Within about 5 F. of the melting point of the waxbased ink.

The bond thus formed has a sufficiently high shear strength to be suitable for the manufacturing operation, but has a very small amount of peel strength so that the fastened end of the ribbon will be able to peel off the core without any noticeable build up of tension within a typewriter.

At the same time that the ribbon 1 is being heated by the element 26, the knife edge 27 will sever the ribbon to permit removal of previously wound ribbon assemblies. Although in this illustration, the heating and severing operations were shown to take place simultaneously, it is recognized that either could precede the other without departing from the spirit and scope of this invention. However, it will generally be most convenient to perform the heating and severing operations simultaneously, or to perform the heating operation be fore the severing operation.

While, in the process described above, the wax base of the carbon ink itself was the bonding agent, the process will produce the same advantageous results if the core upon which a ribbon is to be wound is first coated with a suitable wax and the above-described process is then carried out. This alternative embodiment of first coating the core with wax and then heat sealing a ribbon to it is particularly useful when the ink used on the ribbon does not contain waxes suitable for the heat sealing process.

Generally, in order to obtain a satisfactory bond between a ribbon and a core, it is preferable to use a relatively smooth surfaced core. However, in situations where a core made of porous or rough material is used, the alternative embodiment of the invention wherein the core is first coated with a layer of wax, will produce satisfactory results. For example, if the core is made of a rough-surfaced cardboard-like material, first coating the core with a layer of wax and then using the heat sealing process will yield the best results.

When the alternative of first coating the core with wax is used, one may use any of a large number of waxes or Wax mixtures to coat the core. The ribbon to be attached to the core is then placed in contact with the core and heat applied as has been described above.

For example, Montan, carnauba and parafiin have all been found to be suitable waxes for this process. Each may be used alone or in varying combinations with one or both of the others. The table below lists each of these waxes together with its melting point and a range within which is the suggested minimum temperature to which the wax should be heated. This suggested minimum temperature is approximately 5 F. below the melting point of the wax.

It will be noted that the melting point of each of the waxes is given as a range of temperatures rather than as one single temperature. This is because the wax passes from a solid to a plastic to a liquid state and it is diificult to define a specific melting point. The minimum preferred temperature is also set out as being a range of temperatures for the same reason.

When any of the above waxes are mixed with other waxes, the mixture will have another melting point, generally somewhere between the melting points of the waxes comprising the mixture. When such mixtures are used in the heat sealing process, the minimum preferred temperature to which the wax should be heated can be found by subtracting 5 F. from the melting point of the mixture. Although lower temperatures can be used, the results produced by using lower temperatures are generally not as good.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. A process for producing a high shear strength negligible peel strength bond between a printing machine ribbon and a core, said printing machine ribbon being coated on one face with a wax-based ink, comprising the steps of:

placing the inked face of said printing machine ribbon in intimate contact with the periphery of said core; and

heating said wax-based ink to at least a plastic state;

whereby the wax base of said wax-based ink, upon cooling, bonds said printing machine ribbon to said core.

2. The process of claim 1 wherein:

the temperature to which said wax-based ink is heated is within approximately 10 F. of the melting temperature of the wax base of said wax-based ink.

3. As an article of manufacture,

a bond between a printing machine ribbon and a core manufactured in accordance with the process of claim 1.

4. A process for producing a high shear strength negligible peel strength bond between a printing machine ribbon and a core comprising the steps of:

coating said core with wax;

contacting the periphery of said core with said printing machine ribbon;

heating said wax to at least a plastic state; and

cooling said wax to a solid state;

whereby said wax bonds said printing machine ribbon to said core.

5. The process of claim 4 wherein:

the temperature to which said wax is heated is within approximately 10 F. of the melting temperature of the wax.

6. As an article of manufacture,

a bond between a printing machine ribbon and a core manufactured in accordance with the process of claim 4.

7. A printing machine ribbon assembly comprising:

a core;

a printing machine ribbon wound on said core; and

a body of material releasably bonding part of said ribbon to the periphery of said core, said body of material consisting essentially of at least one wax.

8. A printing machine ribbon assembly comprising:

a core; and

a printing machine ribbon wound on said core;

said printing machine ribbon comprising a thin flexible substrate coated with a body of material containing at least one Wax;

References Cited UNITED STATES PATENTS Amiss 197-172 Newman 197-172 Wharton.

Zaiser 197-172 Yawger et a1 197-172 Arena et al. 206-59 said body of material releasably bonding part of said 10 WILLIAM T DIYSON JR Primary Examiner ribbon to the periphery of said core. 

8. A PRINTING MACHINE RIBBON ASSEMBLY COMPRISING: A CORE; AND A PRINTING MACHINE RIBBON WOUND ON SAID CORE; SAID PRINTING MACHINE RIBBON COMPRISING A THIN FLEXIBLE SUBSTRATE COATED WITH A BODY OF MATERIAL CONTAINING AT LEAST ONE WAX; SAID BODY OF MATERIAL RELEASABLY BONDING PART OF SAID RIBBON TO THE PERIPHERY OF SAID CORE. 